An analysis of David J. Linden’s thoughts on sex and love in chapter six of his book The Accidental Mind.

David J. Linden’s book The Accidental Mind talks about the relationship between love and sex which he analyzes from a neurobiological perspective. He takes some controversial stances on the evolution and origins of sexual behavior, specifically monogamy, and gender identity by comparison of brain structure, sectional neurological activity and behavior and offers some intriguing conceptual support for each of his arguments. Set below are some examples of biological, genetic, and anthropological supports and arguments on his ideas.

He begins his analysis on the origin of monogamistic practices by comparing humans and nonhuman animals and uses this as a basis for explaining “normative human sexual practices.” He argues that the “inelegant brain design” of humans has led to monogamy. He states that the setup is a direct result of the relatively slow neurological and physical maturation of humans and this allows a greater support system for the positive growth of the individual. The female, through a variety of behaviors, forces the males to stay making it far easier for the offspring to find proper sustenance (149-151.) This is actually a space of much debate among anthropologists. David’s conceptual argument is backed by Philip L. Reno and his colleagues who were also under the impression that humans have been historically monogamous. They found through a statistical analysis of Australopithecus afarensis’ fossils’ presence of dimorphism that monogamous have likely existed for between 2 and 3 million years among human ancestors (9405-9409.) They discovered a relatively strong correlation of recessive genes among the size and spacing of facial and cranial bone structure meaning a higher probability of single-pair relationship which would lead to a greater diversity in the genepool. However, these findings are countered by a more recent study by Adam D. Gordon and his colleagues who found strong postcranial size discrepancies lending to polygamistic practices. Through use of more modern analysis techniques and a larger sampling size they overturned the previous finding, although there is room for statistical error (311-316.)

Gender identity is a difficult subject as it is often difficult to find a common ground to base definitions on. David analyzed the differences in brain activity, mental function and behavior in both humans and other mammals. He found that males have, on average, slightly larger brains as a whole, larger cerebral cortexes, and far larger interstitial nuclei of the anterior hypothalamus. On the other hand, he found that women have larger corpus callosums and anterior commissures. “In addition to these neuroanatomical differences between men and women the are some consistent behavioral differences.” Women score higher on verbal fluency, social intelligence, empathy and cooperation while men score better on mathematical, spatial and logical reasoning. He argues that we should use this criteria for understanding gender identity. In Behavior Genetics, it was found that heritability between monozygotic twins of gender identity disorder has approximately a .6 correlation lending to a strong link but leading to the question of the influence of environmental factors (251-57.) William G. Reiner and John P. Gearhart found, however that there was an extremely strong biological basis that took far more influence than the upbringing of the individuals. They admitted an environmental element but found it to be largely overshadowed (333-41.)